Objectives: To review the recent literature on the relation between depression and coronary heart disease (CHD), including both etiologic studies (that is, depression preceding development of CHD) and prognostic studies (that is, depression predicting prognosis in established CHD), and to assess the degree to which the literature supports a causal interpretation of the link between depression and CHD.
Method: We searched the MEDLINE, Current Contents, and PsycINFO databases for articles published between December 15, 2003, and December 15, 2005, containing combinations of several key words related to CHD, prognosis, and depression. We reviewed papers for evidence of 6 rule-of-thumb criteria for making causal inferences: objective CHD outcome measures, prospective designs, results showing consistent and strong dose-response relations, adequate covariate adjustment, biological plausibility, and evidence from clinical trials that changing depression alters CHD risk.
Results: We found 8 recent etiologic studies, 16 prognostic studies, 2 publications with both types of data, and 23 review papers. Although there was much methodological variability concerning measurement of depression and assessment of cardiac outcomes, the recent etiologic studies increase the evidence of a role for depression. Recent prognostic data are less consistent. Small studies showing no link between depression and CHD prognosis continue to appear, despite lack of adequate statistical power.
Conclusions: The recent literature continues to support both an etiologic and a prognostic role for depression in CHD. Despite this evidence, there have been few clinical trials of depression treatment in CHD patients and no clinical trials of depression prevention. Additional trials are needed.